JPS61185770A - Developing device - Google Patents

Abstract

PURPOSE:To eliminate the spill of a developer to the outside by providing a developer entry preventing part for preventing the developer from entering at both edges of the tip of a coating blade. CONSTITUTION:The coating blade 36 of a developing machine 17 is made of a thin phosphorous bronze sheet and is flexible. Its nip part G is press-contacted on the peripheral surface of a developing roller 34 in the tangent state, and its tip E is separated from the developing roller 34 and comprises the inlet of the developer. The developer entry preventing part M is installed at both edges of the tip E, while the blade 36 is folded and molded in a reverse V-shape angle by notching previously the both edges of the tip E, and is made into the developer entry preventing part M. Its tip contacts the developing roller 34 and picks up the developer instead of passing the developer. A seal member 41 made of 'Teflon(R)' is installed in the angle-shaped entry preventing part M to prevent the developer from entering in the lateral direction.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a developing device used in a copying machine or the like, and in particular, a flexible coating blade is placed facing a moving developer carrier, and a developer is placed between the two. The present invention relates to a developing device which develops an electrostatic latent image formed on an image carrier by introducing a developer and forming a thin layer of developer on the developer carrier by frictional charging.

[Technical background of the invention and its problems]

Conventional developing devices used in copying machines and the like include a two-component developing method that uses a developing agent that is a mixture of non-magnetic toner and a carrier that charges the toner, and a developer that contains a magnetic material in advance. There is a magnetic component phenomenon method in which development is performed using a magnetic component. In the former two-component development method, the quality of the developed image will deteriorate unless the mixing ratio of non-magnetic toner and carrier is maintained constant, so a toner density control mechanism or the like is required to control this mixing ratio within a certain range. There were many disadvantages, such as a complicated configuration and high cost. On the other hand, in the latter magnetic component development method, there is no problem of controlling toner density as in the former, but since the developer contains about 40 to 5 Qwt% of magnetic material, coloring properties are poor. There were problems such as difficulty in color development. Furthermore, in both the former two-component development method and the latter magnetic-component development method, since the developer is magnetically attached to the developer carrier, it is necessary to use a magnetic roller, which also increases the cost. This caused the water to become swampy.

Therefore, recently, as a method to solve the above problem,
A non-magnetic component development method has been proposed in which development is performed using a non-magnetic one-component developer. This example is shown in Figures 6 to 8.
To explain with a diagram, first, in FIG. 6, reference numeral 1 indicates an electrostatic latent image on a photoreceptor 2, which is an image bearing member of a copying machine, visualized by a non-magnetic one-component developer (hereinafter simply referred to as developer). This is a developing device. This is box 3 that stores the developer.
There is a rotating developer carrier (hereinafter referred to as a developing roller) 4 in the opening of the opening, and a holder 5 is placed on the developing roller 4.
A coating blade 6 is provided supported by. Further, a developer backflow prevention blade 7 is arranged below the developing roller 4, and a developer recovery brush 8 is provided inside the box 3. Furthermore, seal members 9 for preventing developer leakage are provided at both ends of the box 3.

The coating blade 6 is a thin flexible sheet as shown in FIG. This is referred to as a nip portion G that is pressed into contact. Further from the nip portion G, the tip side portion E is the developing roller 4.
The developer inlets are spaced apart from each other so as to float therebetween, and a developer inlet opening which widens out in a trumpet-like cross section is formed between them.

Further, a developing bias voltage is applied to the coating blade 6 along with the developing roller 4 by a bias power source 1o.

As the developing roller 54 rotates, the developer in the box 3 is introduced into the developer inlet between the tip side E of the coating blade 6 and the developing roller 4. The developer is triboelectrically charged by the nip portion G and deposited on the developing roller 4 to continuously form a thin developer layer A, which forms an electrostatic latent image on the photoreceptor 2. Develop. That is, a visible image B is created by attaching a developer to the electrostatic latent image on the photoreceptor 2. The residual developer on the circumferential surface of the developing roller 4 after development returns to the box 3 through a gap with the lower developer backflow prevention blade 7, and is scraped off by a collection brush 8 and collected. In this way, new developer is constantly supplied to the circumferential surface of the developing roller 4 to perform development.

Furthermore, since it is non-magnetic, color development is easily possible.

By the way, the above-mentioned non-magnetic-component developing type developing device 2
In this case, there is a large amount of developer that drips to the outside from both end edges of the developing roller 4, resulting in inconvenient problems such as contamination of various components within the copy line and the copy paper. This is different from the case where the magnetic roller magnetically attracts the developer and rotates as in the conventional magnetic-component developing method described above, and there is no effect of preventing the developer from falling off due to magnetic attraction, and the 4th circumferential surface of the developing roller Since the developer is simply attached by frictional electrification, the developer that comes out from the outside of both edges of the coating blade 6 to both edges of the peripheral surface of the developing roller 4 is hardly triboelectrically charged and easily falls off. For this reason, seal members 9 are currently provided on both ends as described above, but it is difficult to set conditions for the seal members 9 to fully exhibit the sealing effect, and developer leakage does not occur as much as expected.・Currently, it is not possible to prevent children from falling behind.

That is, the seal member 9 is in contact with the inner surfaces of both end walls of the box 3, and extends from the upper side of the coating blade 6 along both end edges thereof to the lower side around both end edges of the developing roller 4, as shown in FIG. It is set across. However, the coating blade 6 and the developing roller 4 of the sealing member 9
If the contact (pressure state) is weak, the developer will enter from both edge portions F of the tip side portion E of the coating blade 6 floating above the developing roller 4, as shown in FIG.
As shown by the arrows in the figure, a large amount of the coating blade passes through the inner surface of the sealing member 9 from the outside of both ends of the coating blade 6, leaks out to both ends of the peripheral surface of the developing roller 4, and falls outside.

Conversely, when the sealing member 9 is strongly pressed as shown in FIG. 8, both edge portions F of the tip end side E of the coating blade 6 are pressed so as to come into contact with the developing roller 4, so that the developer is absorbed there. In addition, the contact pressure of the sealing member 9 on the developing roller 4 is increased, so that the developer is prevented from passing through the inner surface of the sealing member 9 from the outer side of both end edges of the coating blade 6. However, in this case, as shown in FIG. 8, the pressure of the sealing member 9 causes deformation of the coating blade 6 in the middle of the coating blade 6, and the coating blade 6 swells up over the nip portion G and floats off the developing roller 4. For this reason, a larger amount of developer enters and comes out of the area D than other normal areas, and the developer layer in that area becomes thicker, resulting in poor image quality during development and also resulting in developer spillage. .

[Purpose of the invention]

This invention has been made based on the above circumstances, so that it is possible to prevent the developer from entering from both edge portions between the developer carrier and the tip of the coating blade, and to prevent the developer from entering the developer carrier from both edge portions on the top of the coating blade. This reduces the amount of developer that comes to the surface and eliminates spillage to the outside, and also enables uniform development over the required area of the developer carrier, excluding both edges, without causing unnecessary deformation of the coating blade. It is an object of the present invention to provide a very convenient developing device that can form a thin layer of agent and develop images with good quality.

[Summary of the Invention] In order to achieve the above-mentioned object, the developing device of the present invention is provided with developer intrusion prevention portions for preventing intrusion of developer at both end edge portions of the tip of the coating blade. This design reduces the amount of developer that comes out at the edges and eliminates spillage.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 4.

First, FIG. 1 is a schematic overall configuration diagram showing an example of a copying machine using a non-magnetic component phenomenon type developing device of the present invention. There are provided an exposure device such as an exposure lamp 13 that irradiates a document (not shown) set on the holder, and a lens system 14 such as Cellhook (trade name) that receives reflected light from the exposure lamp 13 and transmits the collected light.

Further, there is a rotating drum-shaped photoreceptor 15, which is a type of image carrier, below the photoreceptor 15, and chargers 16. A developing device 17 is provided with a transfer charger 18, a cleaner 19, and a discharge lamp 20. While rotating, the photoreceptor 15 is first charged by a charger 16 and then exposed to light reflected from the original through the lens system 14 of the exposure device to form an electrostatic latent image. Photoreceptor 15 is then developed with a non-magnetic-component developer from development device 17 to visualize the electrostatic latent image.

On the other hand, copy paper (transfer paper) (not shown) is fed from a paper feed cassette 21 set at one end of the lower part, and the visible image on the photoreceptor 15 is transferred onto the copy paper by the transfer charger 18. After the transfer, the copy paper is sent to a fixing device 22 such as a heat roller, where the transferred image is fixed, and then transferred to a paper output tray 23 on the other end side.
will be ejected as a copy.

Further, the developer remaining on the photoreceptor 15 after the image transfer is removed and collected by the cleaner 19, and the remaining electrostatic latent image on the photoreceptor 15 is erased by the snow removal lamp 20 to return to the initial state. It has become.

Note that the photoreceptor 15 and a charger 16 disposed around it
．． Developing device 17. The cleaner 19 and the static elimination lamp 20 are installed in a single process case 24 made of carbon-containing black polypropylene or the like and are unitized, and can be detached and attached together during assembly and later maintenance/inspection. ing.

Also, 25 in the map is a control circuit box, 2
6 is a main motor for rotationally driving the photoreceptor 15 and the current Wi device @ 17, and 27 is an ozone filter.

Here, to explain in detail the developing device 17 incorporated into the copying machine as described above, there is a box 33 that is housed in the process case 24 and stores the developer, and the box 33 is directed toward the photoreceptor 15 side. A developing roller 34, which is a developer carrier, is pivotally supported at the opening. This developing roller 3
Reference numeral 4 is an aluminum pipe having a diameter of about 200mm, polished to a mirror surface, sandblasted, and then hard chrome plated, and rotated in synchronization with the photoreceptor 15 in the opposite direction. A coating blade 36 is provided on the circumferential surface of the developing roller 34 and supported by a holder 35 . Further, a developer backflow prevention blade 37 made of Mylar (trade name) with a thickness of about 100 μm is provided on the lower side of the circumferential surface of the developing roller 34 with its base end fixed to the inner bottom wall of the box 33. A developer recovery brush 38 made of 6 denier polypropylene is provided inside the box 33. Further, seal members 39 are provided at both ends inside the box 33.

The coating blade 36 of such a developing device 17
is a flexible one made of a J-phosphor bronze sheet with a thickness of about 0.02 to 0.2 am, and its coating blade 36 is approximately on the circumferential surface of the developing roller 34 as shown in FIGS. 2 and 3. In a tangential state, only the nip portion indicated by G, which is halfway toward the tip (lower end in the figure), faces each other so as to sandwich and press the developer, and the tip portion E is further lifted from the developing roller 34 than the nip portion G. A developer inlet port is formed between the developer inlet port and the developer inlet port, which is separated from the developer inlet port and expands into a trumpet-shaped cross section. In other words, this coating blade 36 has both edge portions of the tip E (portions indicated by F in FIGS. 7 and 8) cut in advance to form a mountain shape (inverted V-shape) as shown in FIG. 4. The developer intrusion prevention part M is formed by bending, and its tip edge contacts the developing roller 34 as shown in FIG. 2, and is configured to scoop up the developer without letting it pass through. Furthermore, the developer intrusion prevention part M
In order to prevent the developer from entering from the side, a sealing member 41 made of Teflon (trade name) felt or the like is provided in the inner mountain-shaped space by adhesion or the like and is formed into an open mountain shape to prevent the developer from entering from the side. It is designed to enhance the prevention effect.

Along both end edges of the coating blade 36, three band-shaped seal members on both end sides are provided as shown in FIG. This sealing member 39 is made of Teflon felt or the like similar to that described above, and is mounted from inside the box 33 so as to be held under appropriate pressure by a support member (not shown) so as to be in pressure contact with both end sides of the coating blade 36 and the developing roller 34. ing.

Note that the developing roller 34 and coating blade 36
Although not shown in the figure, a developing bias voltage (AC 3 kHz, peak-to-peak value 1.
6KV and AC 200μ superimposed) is applied.

In the developing device 17 having the above-described configuration, as the developing roller 34 rotates, the developer in the box 33 is transferred from the developer inlet formed by the tip E of the coating blade 36 and the developing roller 34. The developer is frictionally charged by the nip G to continuously form a thin developer layer A with a thickness of about 30 μm on the circumferential surface of the developing roller 34, thereby forming an electrostatic latent image area on the photoreceptor 15. Develop. The remaining developer on the circumferential surface of the developing roller 34 after development is returned to the box 33 through a gap with the lower developer backflow prevention blade 37, scraped off by the collection brush 38, and collected, so that new developer is always available. is supplied onto the developing roller 34 to perform development with stable image quality.

Here, regarding the conventional problem of developer falling from both upper end sides of the developing roller, first, developer intrusion prevention portions M are provided at both end edges of the tip E of the coating blade 36.
is provided, and its tip edge contacts the circumferential surface of the developing roller 34, and does not constitute a developer inlet opening that floats up from the developing roller 34 and has a large trumpet-shaped cross section like the other tip E, so both edges thereof Since the intrusion of the developer from the portion is almost eliminated and the seal members 39 on both end sides are pressed together, the developer passes through the outside of both end edges of the nip portion G of the coating blade 36 and is developed as shown by the arrow in FIG. This eliminates the possibility of leakage to both ends of the circumferential surface of the roller 34 and falling. Furthermore, as mentioned above, since the developer does not enter the both end edges of the coating blade 6, the developer does not enter the nip portion G.
It is coated by frictional electrification and comes out on both ends of the circumferential surface of the developing roller 4, and when it comes to the lower side due to the rotation of the developing roller 4, it hits the lower end of the sealing member 9 and is pushed away, falling down. Things like that will no longer be the case. Moreover, since the portions of the tip E of the coating blade 36 corresponding to both edge portions F shown in FIGS. 7 and 8 are bent into a mountain shape as a developer intrusion prevention portion M, the sealing member 39 is Even when the coating blade 36 is strongly pressed against the circumferential surface of the developing roller 34, the coating blade 36 does not undergo deformation such as partial floating as shown by D in FIG. 8, and the nip portion G extends in the longitudinal direction. Appropriately elastically contacting the circumferential surface of the developing roller 34, a uniform thin developer layer A can be formed over the entire circumferential surface of the developing roller 534 except for both end edges, thereby improving image quality without causing any problems. Good phenomena can be ensured.

Next, another embodiment of the invention will be described with reference to FIG. Unlike the above-mentioned embodiment in which both end edges of the coating blade 36 are bent to form the developer intrusion prevention section M, the developer intrusion prevention section M' is formed separately from the coating blade 36. For example, phosphor bronze blur
The coating blade 3 can be coated by using a small piece of felt, Teflon (trade name), etc., and supporting it with a holder (not shown) protruding from inside the box 33.
6 is located near both ends of the tip E of the coating blade 36, and is provided in contact with the circumferential surface of the developing roller 34 to prevent developer from entering the both ends of the coating blade 36. .

〔Effect of the invention〕

As described above, this invention provides a developer intrusion preventing portion for preventing the intrusion of developer at both end edges of the tip of the coating blade. It is possible to reduce the amount of developer that comes out on both edges of the carrier, eliminating developer spillage to the outside, and also preventing unnecessary deformation of the coating blade. A very convenient developing device that can form a uniform thin layer of developer over the required area excluding both edges on the agent carrier roller and achieve good image quality.This is a very convenient developing device. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the entire copying machine incorporating a developing device showing one embodiment of the present invention, FIG. 2 is a perspective view of the main parts of the developing device of the same embodiment with the sealing member removed, and FIG. The figure is a perspective view of the main part of the developing device with the seal member installed, and the fourth
The figure is a perspective view of a coating blade used in the same developing device, FIG. 5 is a perspective view of the main parts of a developing device showing another embodiment of the present invention with the sealing member removed, and FIG. 6 is a conventional developing device. FIG. 7 is a partial perspective view of the conventional example, and FIG. 8 is a sectional view of the conventional example.
The figure is a partial perspective view showing the problem of the conventional example. 15... Image carrier (photoreceptor), 17... Developing device,
34...Developer carrier (developing roller), 36 River coating blade, G...nip portion, E...tip portion,
M, M'...Developer intrusion prevention section, A...Developer thin layer.

Claims (3)

[Claims] (1) Development in which a coating blade is placed facing a moving developer carrier, and a developer is introduced between the two to form a thin layer of developer on the developer carrier to develop the image carrier. 1. A developing device characterized in that said coating blade is provided with developer intrusion prevention portions at both end edge portions of the tip thereof to prevent intrusion of developer. (2) The developing device according to claim 1, wherein the developer intrusion prevention portion is constructed by bending both end edge portions of the coating blade and bringing them into contact with the developer carrier. . (3) The developing device according to claim 1, wherein the developer intrusion prevention section is constructed by providing a separate part from the coating blade.